867
FXUS65 KBYZ 271745
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
1145 AM MDT SAT JUN 27 2026
KEY MESSAGES
- SEVERE THUNDERSTORMS ARE EXPECTED TO IMPACT MUCH OF THE AREA
TODAY. THERE IS A RISK LEVEL 3 OF 5 FOR SEVERE STORMS EAST OF
ROSEBUD COUNTY. MAIN HAZARDS ARE LARGE HAIL AND STRONG WIND
GUSTS WITH HEAVY RAIN BEING A SECONDARY THREAT. A FEW TORNADOES
ARE POSSIBLE EAST OF BILLINGS-SHERIDAN.
- SHOWERS AND THUNDERSTORMS AGAIN SUNDAY. SEVERE STORMS ARE NOT
EXPECTED THEN.
- SNOW IS LIKELY IN THE MOUNTAINS ABOVE 8000 FEET SATURDAY NIGHT
INTO SUNDAY MORNING AND SUNDAY NIGHT INTO MONDAY, WITH
ACCUMULATIONS OF 1-3".
- WINDY FOR AREAS NORTH OF THE MT/WY BORDER SUNDAY AND MONDAY,
WITH GUSTS TO 30-50 MPH, GREATEST IN THE WESTERN FOOTHILLS.
- WARMING AND DRYING TREND NEXT WEEK.
DISCUSSION
SEVERE WEATHER: THE STORM PREDICTION CENTER HAS ISSUED A LEVEL 3
OUT OF 5 THREAT FOR SEVERE STORMS FOR LOCATIONS EAST OF ROSEBUD
COUNTY TODAY. THE THREAT DECREASES TO THE WEST WITH LOCATIONS FROM
BILLINGS WEST BEING IN A LEVEL 1 OF 5 THREAT. 500 MB TROUGHING TO
OUR WEST WILL CREATE SURFACE LOW PRESSURE OVER WYOMING HELPING TO
ADVECT MOISTURE INTO THE REGION BEFORE BRINGING A COLD FRONT
THROUGH THIS AFTERNOON. STRONG INSTABILITY IS EXPECTED IN THE
HIGHEST RISK AREAS WITH CAPE VALUES IN THE 1-2,000 J/KG RANGE AND
0-6 KM SHEAR IN THE 40-50 KT RANGE.
MODELS ARE TURNING THESE ENVIRONMENTAL FACTORS INTO STRONG STORMS
FOR MUCH OF THE AREA. THE LATEST HREF RUN SHOWS HELICITY TRACKS
MOVING OFF THE BIGHORN MOUNTAINS AND STRENGTHENING OVER SOUTHEAST
MONTANA. THE SOUTHWEST TO NORTHEAST SHEAR PROFILES THAT ARE
EXPECTED TODAY INDICATE STORMS STARTING OUT DISCRETE BEFORE
EVOLVING INTO MCS LIKE STRUCTURES. SOME DETERMINISTIC MODELS SUCH
AS THE HRRR INDICATE A BOWING MCS STRUCTURE OVER SOUTHEAST MONTANA
BRINGING WIND GUSTS IN EXCESS OF 50 KTS. ALL WEATHER THREATS WILL
BE IN PLAY INCLUDING WEAK TORNADOES EAST OF BILLINGS-SHERIDAN,
HAIL >2.0 INCHES, WIND GUSTS >70 MPH, AND HEAVY RAIN.
WINTER WEATHER: COOLER AIR WILL CAUSE PRECIPITATION TO CHANGE TO
SNOW IN THE CRAZY AND BEARTOOTH/ABSAROKA MOUNTAINS AS EARLY AS
TONIGHT. SNOW WILL CONTINUE AT TIMES INTO MONDAY. ACCUMULATIONS
SHOULD REACH 1-3" ALONG THE BEARTOOTH PASS WITH HIGHER AMOUNTS OF
5-9" ELSEWHERE IN THE BEARTOOTH AND CRAZY MOUNTAINS, MAINLY ABOVE
8000 FEET. BECAUSE OF IMPACTS TO TRAVEL ALONG THE BEARTOOTH PASS,
ISSUED A WINTER WEATHER ADVISORY FOR THAT AREA FROM 10PM TONIGHT
TO 6PM MONDAY.
SUNDAY: SCATTERED SHOWERS AND THUNDERSTORMS WILL BE AROUND (20-90%
CHANCE, GREATEST IN WESTERN MOUNTAINS) BUT WITH LOWER DEWPOINTS
AND COOLER AIR IN THE LOWER LEVELS, INSTABILITY WILL BE LOWER,
SO SEVERE THUNDERSTORMS ARE NOT EXPECTED THIS DAY.
WIND: IT WILL BE WINDY ACROSS MUCH OF THE AREA NORTH OF THE MT/WY
BORDER ON SUNDAY AND AGAIN MONDAY, WITH A 700 MB LOW TO OUR NORTH.
LOOK FOR WIND GUSTS OF 30-50 MPH WITH THE STRONGEST GUSTS IN THE
WESTERN FOOTHILLS.
OVERALL THE TREND FOR NEXT WEEK WILL BE TOWARD WARMER AND DRIER
WEATHER. 500 MB PATTERN AND CSU MACHINE LEARNING OUTLOOKS DO NOT
SUGGEST A RISK OF SEVERE THUNDERSTORMS MONDAY AND TUESDAY, BUT A
LOW RISK OF SEVERE WEATHER DOES EXIST FOR AREAS NORTH AND EAST OF
BILLINGS WEDNESDAY-FRIDAY. TORGERSON/RMS
AVIATION
SHOWERS AND THUNDERSTORMS WILL DEVELOP OFF OF THE MOUNTAINS AND
FOOTHILLS LATE THIS MORNING, MOVING FROM SOUTHWEST TO NORTHEAST
THROUGH THE AFTERNOON AND INTO THE EVENING. A FEW THUNDERSTORMS
COULD BE STRONG TO SEVERE, CAPABLE OF PRODUCING VERY LARGE HAIL
(UP TO 2 INCH DIAMETER), WIND GUSTS GREATER THAN 60 KNOTS, AND
HEAVY RAINFALL. THE GREATEST RISK FOR THESE IMPACTS IS OVER SE MT
AND NORTHERN WY, INCLUDING KMLS, KBHK, AND KSHR. HEAVIER SHOWERS
AND THUNDERSTORMS WILL BRING LOWER CEILINGS AND VISIBILITY DOWN
TO 2SM. CATEGORY REDUCTIONS TO IFR ARE POSSIBLE UNDER THESE
STORMS. LOOK FOR CONVECTIVE ACTIVITY TO DIMINISH THROUGH THE LATE
EVENING BEFORE ADDITIONAL SHOWERS ARRIVE OVERNIGHT. MATOS
PRELIMINARY POINT TEMP/POPS
SUN MON TUE WED THU FRI SAT
-----------------------------------------------------------
BIL 052/068 049/068 051/077 052/081 055/087 059/089 058/084
72/W 25/W 31/U 12/T 10/B 11/B 21/U
LVM 043/057 039/058 041/071 043/076 046/081 049/082 048/079
98/T 78/T 53/T 23/T 32/T 22/T 31/U
HDN 050/072 047/071 049/078 050/083 053/090 057/091 056/086
52/W 26/W 21/U 11/B 11/U 11/U 21/U
MLS 054/073 050/071 052/077 053/083 056/090 061/092 061/085
72/N 15/W 21/U 11/B 10/U 11/U 21/U
4BQ 054/076 051/074 052/078 053/084 057/091 061/095 061/086
51/U 24/W 11/U 11/U 11/U 11/U 11/U
BHK 052/076 049/073 049/077 051/084 054/089 058/093 059/085
81/U 44/T 21/N 12/T 11/U 11/U 31/U
SHR 046/072 044/072 045/075 046/081 050/088 054/091 055/084
51/U 23/W 12/T 12/T 01/U 01/U 12/T
BYZ WATCHES/WARNINGS/ADVISORIES
MT...WINTER WEATHER ADVISORY IN EFFECT FROM 10 PM THIS EVENING TO
6 PM MDT MONDAY FOR ZONE 67.
WY...NONE.
WEATHER.GOV/BILLINGS
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